There is a substantial need for a simple, accurate field method for determining physical fitness. Fitness testing by single stage exercises and manual recording of pulse rate after exercise have not correlated well with the multi-stage treadmill and bicycle ergometer methods used in physiological reserach laboratories. The criteria of such a method is simplicity, accuracy and reproducibility. All three of these requirements are important if a true evaluation of physical fitness is to be achieved. It is necessary to provide a cost effective method for evaluating school, community and military fitness programs and it is also desirable to provide a less expensive alternative to traditional exercise testing methods for following individual exercise and cardiac rehabilitation therapy.
There has been no simple accurate technique for estimating an individual's physical fitness level. Questionnaire and interview techniques are inaccurate because people differ in skills and habits, and the same type of work or play may involve vastly different energy expenditures. There is clearly a need for a simple but accurate test of fitness levels, particularly in North America where studies have indicated that fitness levels among North Americans are lower than among genetically similar populations in Europe.
Most studies on the effective exercise on cardiovascular systems have been concerned with th pulse rate and blood pressure response to exertion. Investigators have shown that subjects exhibit a gradually increasing heart rate when work loads are successively increased on a treadmill or on a bicycle ergometer. As the work load increases, the more physically fit individuals will in general show a relatively slower increase in pulse rate, although with actual athletic performance of elite athletes, the opposite may occur. It has also been noted that more physically fit athletes will not only be able to sustain a higher heat rate but will also have their heart rate return to normal more rapidly after stopping activity.
Three basic methods of fitness testing have emerged as somewhat practical for predicting athletic performance. The simplest method is the step test. This test has been described as being an arbitrary criterion based upon test endurance, work accomplished and heart rate. It is not highly reproducible and does not correlate between individuals. The more complex, but also more reliable methods are available speed treadmill testing and bicycle ergometry. Both of these latter methods are good predictors when maximum oxygen consumption is used as an index of cardiovascular efficiency. Because the heart rate response to graded exercise loads correlates well with maximum oxygen intake, this finding has simplified testing and these tests have proven useful in separating groups of athletes from non-athletes. Heart rate monitoring of subjects at graded work loads have also been valuable for prescribing exercise regimens in cardiac rehabilitation. While variable speed treadmill testing is quite reliable, such equipment is very expensive and bulky, making it difficult to move.
Several studies have suggested that the heart rate is a linear function of work speed and as such is somewhat independent of body weight at normal working speeds.
As far as applicant is presently aware, very few patents are even remotely related to the problem of evaluating physical fitness while the patient is exercising. U.s. Pat. No. 1,435,660 discloses an educational appliance which has a sound recording and a visual illustration representing the various movements described in the record. British Pat. No. 718,131 describes a means for detecting and recording electrical changes in the body including, apparently, heart pulse rate. The patent describes various electrodes attached to the body along with a transmitter and receiver for recording and display, which make it possible to measure various physical factors, such as heart pulse rate, while the patient is moving about or is in "situations of particular stress". U.S. Pat. No. 3,846,704 discloses an apparatus for evaluating an athletic performance, but it is primarily concerned with the relationship of the individual athlete with respect to a predetermined performance, such as a world record performance, which the athlete can compare his efforts to during his performance of his event. The apparatus has a programmed central control for sequentially energizing various lights responsive to the programmed optimum performance and the athlete judges his performance relative to the occurrence of various flashing lights as he passes various points on his event. The runner can have his heart pulse rate continuously monitored but the purpose of this is to compare the pulse rate with the optimum one desired for an athlete and to indicate when the heart beat rate departs from a predetermined rate.